2003 GMC Sierra Electircal

So it started with me coming out to my truck one morning and I tried starting my truck, it displayed unknown driver and would fire but shut off as soon as it fired. Did some research and thought it was my remote start. Tried getting that reprogrammed and it wouldn't even let him into the remote start because of the security system. The Internet made it seem like its the ignition switch so I replaced that and it was fine for a little bit. Then it just starting going crazy on me. You'd be driving down the road and it would start with the stereo, it would go on and off then my truck would start saying unknown driver and all my gauges would reset while this is happening I have no power locks, power windows, no power to my four wheel drive shifter, also says service four wheel drive, now every gauge but the speedo and the gas gauge are maxed out when I start it and I have nothing in the driver information center (DIC). I am completely lost with this and vie talked to two mechanics and when I tell them they just look at, me all confused. I really need some help!